<?php
/***************************************************************/
/* PhpCaptcha - A visual and audio CAPTCHA generation library

Software License Agreement (BSD License)

Copyright (C) 2005-2006, Edward Eliot.
All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:

* Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
* Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in the
documentation and/or other materials provided with the distribution.
* Neither the name of Edward Eliot nor the names of its contributors
may be used to endorse or promote products derived from this software
without specific prior written permission of Edward Eliot.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER AND CONTRIBUTORS "AS IS" AND ANY
EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY
DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

Last Updated:  18th April 2006                               */
/***************************************************************/

/************************ Documentation ************************/
/*

Documentation is available at http://www.ejeliot.com/pages/2

*/
/************************ Default Options **********************/


// class defaults - change to effect globally

define('CAPTCHA_SESSION_ID', 'php_captcha');
define('CAPTCHA_WIDTH', 200); // max 500
define('CAPTCHA_HEIGHT', 50); // max 200
define('CAPTCHA_NUM_CHARS', 5);
define('CAPTCHA_NUM_LINES', 70);
define('CAPTCHA_CHAR_SHADOW', true);
define('CAPTCHA_OWNER_TEXT', '');
define('CAPTCHA_CHAR_SET', '1-9'); // defaults to A-Z
define('CAPTCHA_CASE_INSENSITIVE', true);
define('CAPTCHA_BACKGROUND_IMAGES', '');
define('CAPTCHA_MIN_FONT_SIZE', 16);
define('CAPTCHA_MAX_FONT_SIZE', 25);
define('CAPTCHA_USE_COLOUR', true);
define('CAPTCHA_FILE_TYPE', 'jpeg');
define('CAPTCHA_FLITE_PATH', '/usr/bin/flite');
define('CAPTCHA_AUDIO_PATH', '/tmp/'); // must be writeable by PHP process

/************************ End Default Options **********************/

// don't edit below this line (unless you want to change the class!)

class PhpCaptcha {
  var $oImage;
  var $aFonts;
  var $iWidth;
  var $iHeight;
  var $iNumChars;
  var $iNumLines;
  var $iSpacing;
  var $bCharShadow;
  var $sOwnerText;
  var $aCharSet;
  var $bCaseInsensitive;
  var $vBackgroundImages;
  var $iMinFontSize;
  var $iMaxFontSize;
  var $bUseColour;
  var $sFileType;
  var $sCode = '';

  function PhpCaptcha($theme) {


    // get parameters
    $this->aFonts = $theme->getOption('fonts');
    $this->SetNumChars($theme->getOption('num_chars'));
    $this->SetNumLines($theme->getOption('num_lines'));
    $this->DisplayShadow($theme->getOption('shadow'));
    $this->SetOwnerText(CAPTCHA_OWNER_TEXT);
    $this->SetCharSet($theme->getOption('char_set'));
    $this->CaseInsensitive($theme->getOption('case_insensitive'));
    $this->SetBackgroundImages($theme->getOption('background_images'));
    $this->SetMinFontSize($theme->getOption('min_font_size'));
    $this->SetMaxFontSize($theme->getOption('max_font_size'));
    $this->UseColour($theme->getOption('use_color'));
    $this->SetFileType(CAPTCHA_FILE_TYPE);
    $this->SetWidth($theme->getOption('width'));
    $this->SetHeight($theme->getOption('height'));

  }

  function CalculateSpacing() {
    $this->iSpacing = (int)($this->iWidth / $this->iNumChars);
  }

  function SetWidth($iWidth) {
    $this->iWidth = $iWidth;
    if ($this->iWidth > 500) $this->iWidth = 500; // to prevent perfomance impact
    $this->CalculateSpacing();
  }

  function SetHeight($iHeight) {
    $this->iHeight = $iHeight;
    if ($this->iHeight > 200) $this->iHeight = 200; // to prevent performance impact
  }

  function SetNumChars($iNumChars) {
    $this->iNumChars = $iNumChars;
    $this->CalculateSpacing();
  }

  function SetNumLines($iNumLines) {
    $this->iNumLines = $iNumLines;
  }

  function DisplayShadow($bCharShadow) {
    $this->bCharShadow = $bCharShadow;
  }

  function SetOwnerText($sOwnerText) {
    $this->sOwnerText = $sOwnerText;
  }

  function SetCharSet($vCharSet) {
    // check for input type
    if (is_array($vCharSet)) {
      $this->aCharSet = $vCharSet;
    } else {
      if ($vCharSet != '') {
        // split items on commas
        $aCharSet = explode(',', $vCharSet);

        // initialise array
        $this->aCharSet = array();

        // loop through items
        foreach ($aCharSet as $sCurrentItem) {
          // a range should have 3 characters, otherwise is normal character
          if (strlen($sCurrentItem) == 3) {
            // split on range character
            $aRange = explode('-', $sCurrentItem);

            // check for valid range
            if (count($aRange) == 2 && $aRange[0] < $aRange[1]) {
              // create array of characters from range
              $aRange = range($aRange[0], $aRange[1]);
               
              // add to charset array
              $this->aCharSet = array_merge($this->aCharSet, $aRange);
            }
          } else {
            $this->aCharSet[] = $sCurrentItem;
          }
        }
      }
    }
  }

  function CaseInsensitive($bCaseInsensitive) {
    $this->bCaseInsensitive = $bCaseInsensitive;
  }

  function SetBackgroundImages($vBackgroundImages) {
    $this->vBackgroundImages = $vBackgroundImages;
  }

  function SetMinFontSize($iMinFontSize) {
    $this->iMinFontSize = $iMinFontSize;
  }

  function SetMaxFontSize($iMaxFontSize) {
    $this->iMaxFontSize = $iMaxFontSize;
  }

  function UseColour($bUseColour) {
    $this->bUseColour = $bUseColour;
  }

  function SetFileType($sFileType) {
    // check for valid file type
    if (in_array($sFileType, array('gif', 'png', 'jpeg'))) {
      $this->sFileType = $sFileType;
    } else {
      $this->sFileType = 'jpeg';
    }
  }

  function DrawLines() {
    for ($i = 0; $i < $this->iNumLines; $i++) {
      // allocate colour
      if ($this->bUseColour) {
        $iLineColour = imagecolorallocate($this->oImage, rand(100, 250), rand(100, 250), rand(100, 250));
      } else {
        $iRandColour = rand(100, 250);
        $iLineColour = imagecolorallocate($this->oImage, $iRandColour, $iRandColour, $iRandColour);
      }

      // draw line
      imageline($this->oImage, rand(0, $this->iWidth), rand(0, $this->iHeight), rand(0, $this->iWidth), rand(0, $this->iHeight), $iLineColour);
    }
  }

  function DrawOwnerText() {
    // allocate owner text colour
    $iBlack = imagecolorallocate($this->oImage, 0, 0, 0);
    // get height of selected font
    $iOwnerTextHeight = imagefontheight(2);
    // calculate overall height
    $iLineHeight = $this->iHeight - $iOwnerTextHeight - 4;
     
    // draw line above text to separate from CAPTCHA
    imageline($this->oImage, 0, $iLineHeight, $this->iWidth, $iLineHeight, $iBlack);
     
    // write owner text
    imagestring($this->oImage, 2, 3, $this->iHeight - $iOwnerTextHeight - 3, $this->sOwnerText, $iBlack);
     
    // reduce available height for drawing CAPTCHA
    $this->iHeight = $this->iHeight - $iOwnerTextHeight - 5;
  }

  function GenerateCode() {
    // reset code
    $this->sCode = '';
     
    // loop through and generate the code letter by letter
    for ($i = 0; $i < $this->iNumChars; $i++) {
      if (count($this->aCharSet) > 0) {
        // select random character and add to code string
        $this->sCode .= rand(0,9);
      } else {
        // select random character and add to code string
        $this->sCode .= rand(0,9);
      }
    }
     
    // save code in session variable
    if ($this->bCaseInsensitive) {
      $_SESSION[CAPTCHA_SESSION_ID] = strtoupper($this->sCode);
    } else {
      $_SESSION[CAPTCHA_SESSION_ID] = $this->sCode;
    }
  }

  function DrawCharacters() {
    // loop through and write out selected number of characters
    for ($i = 0; $i < strlen($this->sCode); $i++) {
      // select random font
      $sCurrentFont = $this->aFonts[array_rand($this->aFonts)];

      // select random colour
      if ($this->bUseColour) {
        $iTextColour = imagecolorallocate($this->oImage, rand(0, 100), rand(0, 100), rand(0, 100));

        if ($this->bCharShadow) {
          // shadow colour
          $iShadowColour = imagecolorallocate($this->oImage, rand(0, 100), rand(0, 100), rand(0, 100));
        }
      } else {
        $iRandColour = rand(0, 100);
        $iTextColour = imagecolorallocate($this->oImage, $iRandColour, $iRandColour, $iRandColour);

        if ($this->bCharShadow) {
          // shadow colour
          $iRandColour = rand(0, 100);
          $iShadowColour = imagecolorallocate($this->oImage, $iRandColour, $iRandColour, $iRandColour);
        }
      }

      // select random font size
      $iFontSize = rand($this->iMinFontSize, $this->iMaxFontSize);

      // select random angle
      $iAngle = rand(-30, 30);

      // get dimensions of character in selected font and text size
      $aCharDetails = imageftbbox($iFontSize, $iAngle, $sCurrentFont, $this->sCode[$i], array());

      // calculate character starting coordinates
      $iX = $this->iSpacing / 4 + $i * $this->iSpacing;
      $iCharHeight = $aCharDetails[2] - $aCharDetails[5];
      $iY = $this->iHeight / 2 + $iCharHeight / 4;

      // write text to image
      imagefttext($this->oImage, $iFontSize, $iAngle, $iX, $iY, $iTextColour, $sCurrentFont, $this->sCode[$i], array());

      if ($this->bCharShadow) {
        $iOffsetAngle = rand(-30, 30);
         
        $iRandOffsetX = rand(-5, 5);
        $iRandOffsetY = rand(-5, 5);
         
        imagefttext($this->oImage, $iFontSize, $iOffsetAngle, $iX + $iRandOffsetX, $iY + $iRandOffsetY, $iShadowColour, $sCurrentFont, $this->sCode[$i], array());
      }
    }
  }

  function WriteFile($sFilename) {
    if ($sFilename == '') {
      // tell browser that data is jpeg
      header("Content-type: image/$this->sFileType");
    }
     
    switch ($this->sFileType) {
      case 'gif':
        $sFilename != '' ? imagegif($this->oImage, $sFilename) : imagegif($this->oImage);
        break;
      case 'png':
        $sFilename != '' ? imagepng($this->oImage, $sFilename) : imagepng($this->oImage);
        break;
      default:
        $sFilename != '' ? imagejpeg($this->oImage, $sFilename) : imagejpeg($this->oImage);
    }
  }

  function Create($sFilename = '') {
    // check for required gd functions
    if (!function_exists('imagecreate') || !function_exists("image$this->sFileType") || ($this->vBackgroundImages != '' && !function_exists('imagecreatetruecolor'))) {
      return false;
    }
     
    // get background image if specified and copy to CAPTCHA
    if (is_array($this->vBackgroundImages) || $this->vBackgroundImages != '') {
      // create new image
      $this->oImage = imagecreatetruecolor($this->iWidth, $this->iHeight);

      // create background image
      if (is_array($this->vBackgroundImages)) {
        $iRandImage = array_rand($this->vBackgroundImages);
        $oBackgroundImage = imagecreatefromjpeg($this->vBackgroundImages[$iRandImage]);
      } else {
        $oBackgroundImage = imagecreatefromjpeg($this->vBackgroundImages);
      }

      // copy background image
      imagecopy($this->oImage, $oBackgroundImage, 0, 0, 0, 0, $this->iWidth, $this->iHeight);

      // free memory used to create background image
      imagedestroy($oBackgroundImage);
    } else {
      // create new image
      $this->oImage = imagecreate($this->iWidth, $this->iHeight);
    }
     
    // allocate white background colour
    imagecolorallocate($this->oImage, 255, 255, 255);
     
    // check for owner text
    if ($this->sOwnerText != '') {
      $this->DrawOwnerText();
    }
     
    // check for background image before drawing lines
    if (!is_array($this->vBackgroundImages) && $this->vBackgroundImages == '') {
      $this->DrawLines();
    }
     
    $this->GenerateCode();
    $this->DrawCharacters();
     
    // write out image to file or browser
    $this->WriteFile($sFilename);
     
    // free memory used in creating image
    imagedestroy($this->oImage);
     
    return true;
  }

  // call this method statically
  public static function Validate($sUserCode, $bCaseInsensitive = true) {
    if ($bCaseInsensitive) {
      $sUserCode = strtoupper($sUserCode);
    }
     
    if (!empty($_SESSION[CAPTCHA_SESSION_ID]) && $sUserCode == $_SESSION[CAPTCHA_SESSION_ID]) {
      // clear to prevent re-use
      unset($_SESSION[CAPTCHA_SESSION_ID]);

      return true;
    }
     
    return false;
  }
}

// this class will only work correctly if a visual CAPTCHA has been created first using PhpCaptcha
class AudioPhpCaptcha {
  var $sFlitePath;
  var $sAudioPath;
  var $sCode;

  function AudioPhpCaptcha(
  $sFlitePath = CAPTCHA_FLITE_PATH, // path to flite binary
  $sAudioPath = CAPTCHA_AUDIO_PATH // the location to temporarily store the generated audio CAPTCHA
  ) {
    $this->SetFlitePath($sFlitePath);
    $this->SetAudioPath($sAudioPath);
     
    // retrieve code if already set by previous instance of visual PhpCaptcha
    if (isset($_SESSION[CAPTCHA_SESSION_ID])) {
      $this->sCode = $_SESSION[CAPTCHA_SESSION_ID];
    }
  }

  function SetFlitePath($sFlitePath) {
    $this->sFlitePath = $sFlitePath;
  }

  function SetAudioPath($sAudioPath) {
    $this->sAudioPath = $sAudioPath;
  }

  function Mask($sText) {
    $iLength = strlen($sText);
     
    // loop through characters in code and format
    $sFormattedText = '';
    for ($i = 0; $i < $iLength; $i++) {
      // comma separate all but first and last characters
      if ($i > 0 && $i < $iLength - 1) {
        $sFormattedText .= ', ';
      } elseif ($i == $iLength - 1) { // precede last character with "and"
        $sFormattedText .= ' and ';
      }
      $sFormattedText .= $sText[$i];
    }
     
    $aPhrases = array(
            "The %1\$s characters are as follows: %2\$s",
            "%2\$s, are the %1\$s letters",
            "Here are the %1\$s characters: %2\$s",
            "%1\$s characters are: %2\$s",
            "%1\$s letters: %2\$s"
            );
             
            $iPhrase = array_rand($aPhrases);
             
            return sprintf($aPhrases[$iPhrase], $iLength, $sFormattedText);
  }

  function Create() {
    $sText = $this->Mask($this->sCode);
    $sFile = md5($this->sCode.time());
     
    // create file with flite
    shell_exec("$this->sFlitePath -t \"$sText\" -o $this->sAudioPath$sFile.wav");
     
    // set headers
    header('Content-type: audio/x-wav');
    header("Content-Disposition: attachment;filename=$sFile.wav");
     
    // output to browser
    echo file_get_contents("$this->sAudioPath$sFile.wav");
     
    // delete temporary file
    @unlink("$this->sAudioPath$sFile.wav");
  }
}

// example sub class
class PhpCaptchaColour extends PhpCaptcha {
  function PhpCaptchaColour($aFonts, $iWidth = CAPTCHA_WIDTH, $iHeight = CAPTCHA_HEIGHT) {
    // call parent constructor
    parent::PhpCaptcha($aFonts, $iWidth, $iHeight);
     
    // set options
    $this->UseColour(true);
  }
}

